BUPRENORPHINE HYDROCHLORIDE

Buprenorphine hydrochloride is a partial opioid agonist. The chemical name of buprenorphine hydrochloride is 17-(cyclopropylmethyl)-α-(1,1-dimethylethyl)-4,5-epoxy 18,19-dihydro-3-hydroxy-6-methoxy-α-methyl-6,14-ethenomorphinan-7-methanol, hydrochloride [5α, 7α(S)]. Buprenorphine hydrochloride is a white powder, weakly acidic and with limited solubility in water. Buprenorphine hydrochloride injection is a clear, sterile, injectable agonist-antagonist analgesic intended for intravenous or intramuscular administration. Each mL of buprenorphine hydrochloride injection contains 0.324 mg buprenorphine hydrochloride (equivalent to 0.3 mg buprenorphine), 50 mg anhydrous dextrose, water for injection and HCl to adjust pH to 3.5 to 5.5. Buprenorphine hydrochloride has the molecular formula, C 29 H 41 NO 4 ∙HCl and the molecular weight of 504.09. It has the following structural formula: Chemical Structure

Buprenorphine hydrochloride injection is indicated for the management of pain severe enough to require an opioid analgesic and for which alternate treatments are inadequate. Limitations of Use: Because of the risks of addiction, abuse, misuse, overdose, and death, which can occur at any dosage or duration and persist over the course of therapy [see WARNINGS ], reserve opioid analgesics, including buprenorphine hydrochloride, for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.

• Buprenorphine hydrochloride should be prescribed only by healthcare professionals who are knowledgeable about the use of opioids and how to mitigate the associated risks. • Use the lowest effective dosage for the shortest duration of time consistent with individual patient treatment goals [see WARNINGS ]. Because the risk of overdose increases as opioid doses increase, reserve titration to higher doses of buprenorphine hydrochloride for patients in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks. • Many acute pain conditions (e.g., the pain that occurs with a number of surgical procedures or acute musculoskeletal injuries) require no more than a few days of an opioid analgesic. Clinical guidelines on opioid prescribing for some acute pain conditions are available. • There is variability in the opioid analgesic dose and duration needed to adequately manage pain due both to the cause of pain and to individual patient factors. Initiate the dosing regimen for each patient individually, taking into account the patient’s underlying cause and severity of pain, prior analgesic treatment and response, and risk factors for addiction, abuse, and misuse [see WARNINGS ]. • Respiratory depression can occur at any time during opioid therapy, especially when initiating and following dosage increases with buprenorphine hydrochloride. Consider this risk when selecting an initial dose and when making dose adjustments [see WARNINGS ]. • Inspect buprenorphine hydrochloride injection for particulate matter and discoloration prior to administration. Dosing Adults and Pediatric Patients over 12 years of age The initial starting dose is 1 mL buprenorphine hydrochloride injection (0.3 mg buprenorphine) given by deep intramuscular or slow (over at least 2 minutes) intravenous injection at up to 6-hour intervals, as needed. Repeat once (up to 0.3 mg) if required, 30 to 60 minutes after initial dosage, giving consideration to previous dose pharmacokinetics, and thereafter only as needed. In high-risk patients (e.g., elderly, debilitated, presence of respiratory disease, etc.) and/or in patients where other CNS depressants are present, such as in the immediate postoperative period, the dose should be limited to the minimum required. Extra caution should be exercised with the intravenous route of administration, particularly with the initial dose. Occasionally, it may be necessary to administer single doses of up to 0.6 mg to adults depending on the severity of the pain and the response of the patient. This dose should only be given intramuscularly and only to adult patients who are not in a high risk category [see WARNINGS , PRECAUTIONS ]. At this time, there are insufficient data to recommend single doses greater than 0.6 mg for long-term use. Pediatric Patients Buprenorphine hydrochloride has been used in pediatric patients 2 to 12 years of age at doses between 2 to 6 micrograms/kg of body weight given every 4 to 6 hours. There is insufficient experience to recommend a dose in infants below the age of two years, single doses greater than 6 micrograms/kg of body weight, or the use of a repeat or second dose at 30 to 60 minutes (such as is used in adults). Since there is some evidence that not all pediatric patients clear buprenorphine faster than adults, fixed interval or "round-the-clock" dosing should not be undertaken until the proper inter-dose interval has been established by clinical observation of the child. Healthcare providers should recognize that, as with adults, some pediatric patients may not need to be remedicated for 6 to 8 hours. Safety and Handling Buprenorphine hydrochloride injection is supplied in sealed cartridges and poses no known environmental risk to healthcare providers. Accidental dermal exposure should be treated by removal of any contaminated clothing and rinsing the affected area with water. Buprenorphine is a potent opioid and, like all drugs of this class, has been associated with abuse and dependence among healthcare providers. To control the risk of diversion, it is recommended that measures appropriate to the health care setting be taken to provide rigid accounting, control of wastage, and restriction of access. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Buprenorphine hydrochloride is contraindicated in patients with: • Significant respiratory depression [see WARNINGS ]. • Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment [see WARNINGS ]. • Known or suspected gastrointestinal obstruction, including paralytic ileus [see WARNINGS ]. • Hypersensitivity to buprenorphine (e.g., anaphylaxis) or any other ingredient in buprenorphine hydrochloride [see WARNINGS ].

The most frequent side effect in clinical studies involving 1,133 patients was sedation which occurred in approximately two-thirds of the patients. Although sedated, these patients could easily be aroused to an alert state. Other less frequent adverse reactions occurring in 5 to 10% of the patients were: Nausea Dizziness/Vertigo Occurring in 1 to 5% of the patients: Sweating Headache Hypotension Nausea/Vomiting Vomiting Hypoventilation Miosis The following adverse reactions were reported to have occurred in less than 1% of the patients: CNS Effect: confusion, blurred vision, euphoria, weakness/fatigue, dry mouth, nervousness, depression, slurred speech, paresthesia. Cardiovascular: hypertension, tachycardia, bradycardia. Gastrointestinal: constipation. Respiratory: dyspnea, cyanosis. Dermatological: pruritus. Ophthalmological: diplopia, visual abnormalities. Miscellaneous: injection site reaction, urinary retention, dreaming, flushing/warmth, chills/cold, tinnitus, conjunctivitis, Wenckebach block, and psychosis. Other effects observed infrequently include malaise, hallucinations, depersonalization, coma, dyspepsia, flatulence, apnea, rash, amblyopia, tremor, and pallor. The following reactions have been reported to occur rarely: loss of appetite, dysphoria/agitation, diarrhea, urticaria, and convulsions/lack of muscle coordination. Allergic Reactions: Cases of acute and chronic hypersensitivity to buprenorphine have been reported both in clinical trials and in the postmarketing experience of buprenorphine and other buprenorphine-containing products. The most common signs and symptoms include rashes, hives, and pruritus. Cases of bronchospasm, angioneurotic edema, and anaphylactic shock have been reported. A history of hypersensitivity to buprenorphine is a contraindication to buprenorphine. In the United Kingdom, buprenorphine hydrochloride was made available under monitored release regulation during the first year of sale, and yielded data from 1,736 physicians on 9,123 patients (17,120 administrations). Data on 240 children under the age of 18 years were included in this monitored release program. No important new adverse effects attributable to buprenorphine hydrochloride were observed. Postmarketing Experience Serotonin syndrome: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs. Adrenal insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Androgen deficiency: Cases of androgen deficiency have occurred with use of opioids for an extended period of time [see CLINICAL PHARMACOLOGY: Pharmacodynamics ]. Hyperalgesia and Allodynia: Cases of hyperalgesia and allodynia have been reported with opioid therapy of any duration [see WARNINGS ]. Hypoglycemia: Cases of hypoglycemia have been reported in patients taking opioids. Most reports were in patients with at least one predisposing risk factor (e.g., diabetes). Opioid-induced esophageal dysfunction (OIED): Cases of OIED have been reported in patients taking opioids and may occur more frequently in patients taking higher doses of opioids, and/or in patients taking opioids longer term [see WARNINGS ]. Adverse Reactions from Observational Studies A prospective, observational cohort study estimated the risks of addiction, abuse, and misuse in patients initiating long-term use of Schedule II opioid analgesics between 2017 and 2021. Study participants included in one or more analyses had been enrolled in selected insurance plans or health systems for at least one year, were free of at least one outcome at baseline, completed a minimum number of follow-up assessments, and either: 1) filled multiple extended-release/long-acting opioid analgesic prescriptions during a 90-day period (n=978); or 2) filled any Schedule II opioid analgesic prescriptions covering at least 70 of 90 days (n=1,244). Those included also had no dispensing of the qualifying opioids in the previous 6 months. Over 12 months: • approximately 1% to 6% of participants across the two cohorts newly met criteria for addiction, as assessed with two validated interview-based measures of moderate-to-severe opioid use disorder based on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria, and • approximately 9% and 22% of participants across the two cohorts newly met criteria for prescription opioid abuse and misuse [defined in DRUG ABUSE AND DEPENDENCE ], respectively, as measured with a validated self-reported instrument. A retrospective, observational cohort study estimated the risk of opioid-involved overdose or opioid overdose-related death in patients with new long-term use of Schedule II opioid analgesics from 2006 through 2016 (n=220,249). Included patients had been enrolled in either one of two commercial insurance programs, one managed care program, or one Medicaid program for at least 9 months. New long-term use was defined as having Schedule II opioid analgesic prescriptions covering at least 70 days’ supply over the 3 months prior to study entry and none during the preceding 6 months. Patients were excluded if they had an opioid-involved overdose in the 9 months prior to study entry. Overdose was measured using a validated medical code-based algorithm with linkage to the National Death Index database. The 5-year cumulative incidence estimates for opioid-involved overdose or opioid overdose-related death ranged from approximately 1.5% to 4% across study sites, counting only the first event during follow-up. Approximately 17% of first opioid overdoses observed over the entire study period (5-11 years, depending on the study site) were fatal. Higher baseline opioid dose was the strongest and most consistent predictor of opioid-involved overdose or opioid overdose-related death. Study exclusion criteria may have selected patients at lower risk of overdose, and substantial loss to follow-up (approximately 80%) also may have biased estimates. The risk estimates from the studies described above may not be generalizable to all patients receiving opioid analgesics, such as those with exposures shorter or longer than the duration evaluated in the studies.

Clinically significant drug interactions with Buprenorphine Hydrochloride Benzodiazepines and Other Central Nervous System (CNS) Depressants Clinical Impact: Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Intervention: Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor patients closely for signs of respiratory depression and sedation [see WARNINGS ]. Examples: Benzodiazepines and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids, alcohol. Inhibitors of CYP3A4 Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inhibitors can increase the plasma concentration of buprenorphine, resulting in increased or prolonged opioid effects, particularly when an inhibitor is added after a stable dose of buprenorphine hydrochloride is achieved. After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, the buprenorphine plasma concentration will decrease [see CLINICAL PHARMACOLOGY: Pharmacokinetics ], potentially resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to buprenorphine. Intervention: If concomitant use is necessary, consider dosage reduction of buprenorphine hydrochloride until stable drug effects are achieved. Monitor patients for respiratory depression and sedation. If a CYP3A4 inhibitor is discontinued, consider increasing the buprenorphine hydrochloride dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir). CYP3A4 Inducers Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inducers can decrease the plasma concentration of buprenorphine [see CLINICAL PHARMACOLOGY: Pharmacokinetics ], potentially resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to buprenorphine. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the buprenorphine plasma concentration will increase [see CLINICAL PHARMACOLOGY: Pharmacokinetics ], which could increase or prolong both therapeutic effects and adverse reactions and may cause serious respiratory depression. Intervention: If concomitant use is necessary, consider increasing the buprenorphine hydrochloride dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. If a CYP3A4 inducer is discontinued, consider buprenorphine hydrochloride dosage reduction and monitor for signs of respiratory depression and sedation. Examples: Rifampin, carbamazepine, phenytoin Serotonergic Drugs Clinical Impact: The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Intervention: If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue buprenorphine hydrochloride if serotonin syndrome is suspected. Examples: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Monoamine Oxidase Inhibitors (MAOIs) Clinical Impact: MAOI interactions with opioids may manifest as serotonin syndrome opioid toxicity (e.g., respiratory depression, coma). Intervention: The use of buprenorphine hydrochloride is not recommended for patients taking MAOIs or within 14 days of stopping such treatment. Examples: Phenelzine, tranylcypromine, linezolid Mixed Agonist/Antagonist and Partial Agonist Opioid Analgesics Clinical Impact: May reduce the analgesic effect of buprenorphine hydrochloride and/or precipitate withdrawal symptoms. Intervention: Avoid concomitant use. Examples: Butorphanol, nalbuphine, pentazocine Muscle Relaxants Clinical Impact: Buprenorphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. Intervention: Monitor patients for signs of respiratory depression that may be greater than otherwise expected, decrease the dosage of buprenorphine hydrochloride and/or the muscle relaxant as necessary. Examples: Cyclobenzaprine, metaxalone. Diuretics Clinical Impact: Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Intervention: Monitor patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed. Anticholinergic Drugs Clinical Impact: The concomitant use of anticholinergic drugs may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Intervention: Monitor patients for signs of urinary retention or reduced gastric motility when buprenorphine hydrochloride is used concomitantly with anticholinergic drugs. Antiretrovirals: Nucleoside reverse transcriptase inhibitors (NRTIs) Clinical Impact: Nucleoside reverse transcriptase inhibitors (NRTIs) do not appear to induce or inhibit the P450 enzyme pathway, thus no interactions with buprenorphine are expected. Intervention: None Antiretrovirals: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) Clinical Impact: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are metabolized principally by CYP3A4. Efavirenz, nevirapine, and etravirine are known CYP3A inducers, whereas delaviridine is a CYP3A inhibitor. Significant pharmacokinetic interactions between NNRTIs (e.g., efavirenz and delavirdine) and buprenorphine have been shown in clinical studies, but these pharmacokinetic interactions did not result in any significant pharmacodynamic effects. Intervention: If prescribing an NNRTI to a patient taking buprenorphine hydrochloride, frequently reevaluate for this interaction and adjust dosing as necessary. Examples: Efavirenz, nevirapine, etravirine, delavirdine Antiretrovirals: Protease inhibitors (PIs) Clinical Impact: Studies have shown some antiretroviral protease inhibitors (PIs) with CYP3A4 inhibitory activity (nelfinavir, lopinavir/ritonavir, ritonavir) have little effect on buprenorphine pharmacokinetic and no significant pharmacodynamic effects. Other PIs with CYP3A4 inhibitory activity (atazanavir and atazanavir/ritonavir) resulted in elevated levels of buprenorphine and norbuprenorphine, and patients in one study reported increased sedation. Symptoms of opioid excess have been found in post-marketing reports of patients receiving buprenorphine and atazanavir with and without ritonavir concomitantly. Intervention: Monitor patients taking buprenorphine hydrochloride and atazanavir with and without ritonavir, and dose reduction of buprenorphine hydrochloride may be warranted. Examples: Atazanavir, ritonavir

Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Protect from prolonged exposure to light. Retain in carton until time of use. Do not freeze. Carpuject™ Single-dose cartridges with Luer Lock are packaged in a Slim-Pak™ tamper detection package. Note that a needle is not included.